Directional receiver



June 4, 1935A` l 'W.KH| EW1ND 2,003,372

DIRECTIONAL RECEIVER Filed Feb. 16, 1933 505mm A ATTORNEY lpafetedflune'4, 1935 l i Walter Khlewindgerlin, Germanyyassignor i TelefunkenGesellschaft fur Drahtlose Tele- -Y graphie m. fb. H., Berlin, Germany,`a corpora-j i Y :e 4tion, of Germany l l f Application February '16,iseaserial No.` 657,069

z 1 .i l InGermany April 1, 1932 e K n SClanis. [Thisinventionrelatesto-a'methodof and arrangement for ascertaining directionin taking bearings 4of electro-'magneticwaves.` .In order toi ascertainfurthermore the sense' t 5 ofrdirectionof electro-magnetic raysfor'which bearing has already `been established by means "of a iframeantenna, itvis a customary methodV to use alinear auxiliary antennawhosevoltage is combined `in l such mannerA 'with that supplied 'bythedirective antenna, that the directional receivingcharacteristicassumesthe shape zof a cardioid.` In order to. determine`thesense of direction, the directive antenna is placed iinto theposition-in vvhichathe` reception is a maximum i reception.` With thisposition-corresponds the f point of the cardioidV for which `thevreception is at maximum oriminimum in accordance with the relativesense of connection of the two an-` tennae. By alternately connecting`the auxiliary antenna to the lone or theother pole of thedirectional-"antenna or i of the circuit `sup1`)lied= by the'latteritcan be determined'by such experi mentation bywhatever connection th'eVsignal 4.5; by a corresponding'V reversal of alswitch.

strength becomes greater thuslascertaining the sense of direction'ofthedirectiverays. i.

l In connecting` the auxiliary antenna'to the one or the other pole ofthedirectional 'antenna or to aY circuit supplied by .the latter l(suchconnec-' tion may either .be adirectone or it may include a specialamplifier) dilculties arev beingmet in that thecapacity of theauxiliaryantenna andof its in,putl connections often cause a consider abledetuning` of the circuits which` previously' had been accuratelyrtunedforthe direction find-1 ing by means `of the framel antenna alone.

` Accordingto thep'esent invention this flavrl.` back .is overcome invthat-the auxiliary antenna` is :continuously coupled to th'e inputcircuit of two `amplifier ltubesgeach of whose output cirV 1 cuitsarecontinuously connectedrespectively to` one of the polesofthejdirectional antennaor of' the V*circuit supplied by the latter,and that for as-i certaining the direction the one or the other ofi ,theampliiiers is rendered electrically eiiective l This invention isbest`described by referring Vto' the:accompanying` drawing in which,`

``Iig.` 1 is aischematic-cir'cuit diagram of ione embodimentl ofv thisinvention;

pointersygiV f Figif is a soin-:maticV circuit ldiagramrof anotherembodiment of this invention wherein the i' directive antennais formedof two` open vertical conductors instead of theframe or loop` antennashown nFg. Y1.; m Q f1 '.7 Figure 1 shows a schematic illustration. ofan embodiment of the arrangement according to the Y,

invention by way of example. Herein is aF-a 1ig.2` is'a.plan view of`the'loopoperating hand" wheel indicatingscale pointer and 'twoauxiliary-l (olyesoV-in Y frame antennaeis the-tube of the input stage vof the receiver; b represents the linear auxiliary i antennadl, d2 aretwo ampliers,*-H+H" are the lpoles' of alamentheating battery, hrand71,2.`

respectively are the heating'resistors and'vsfdesignates a switch. VTheauxiliary-jantennais con?. tinuously coupled with Vthe grids connectedin' parallel of the two amplifiers 011,112. f The 'anodes of theamplifiers are connected tothe polesLrZ` 1'0? across condensers C1, C2.`.Changing potentialsfor theV anodesof tubes d1, vcl2 is supplied froma. source ,-l-A. If the auxiliary antenna'is not used;- (for instanceduring ...direction lndinghwith only-V the frame antenna) the switch sis in the center two amplifiers are in inoperative position.;

position. The heating Lis disconnected anctrthe `For ascertaining theVdirection theV switchI S is 1 several times alternately moved to theleftfand" right whereby the one or.` the other of the amplif-V iiers becomesalternately eiiective'throughclos-f ing of the heatingcurrent so thatthe auxiliary antenna isalternately combined with the frame antenna inequal phase or in opposite, phase.'

TheY conditions, of tuning are thereby notV changed as the two `tubes diand d2 were also pre-I viously connectedlto the poles l and" I f Bymeans ofthe switch'snot only .the 'activa-li tion of the ampliersfdi;d2` can be obtained but also the control of vthe power thereof due tothe adjustment or" the heating resistors.

spectiyely ofthe.` amplifiers besides the method of connecting theheating, could also be obtained by meansof connectinglor varying)l orcon-2` trolling respectively thegrid bias oranodep'otential while theheating is connected. AI

Which, Vthe switch passesfduring its movementzto the left orhright, withsuitableimarkingsby 'which' cilitated vso that the switch sY canbeused-at the same' time as indicator` for the sense of' directiom kAsuitable and often usedA method 'of marking consists in that the twosurfaces are marked l:by vvarious colors forV instance the left eldiblue andthe right ,field in' red.A Two auxiliary point@ ers B and Rfastened on the direction indicating4 wheel P correspond withthese`markingsin`th`at one is marked in blue and the otherlinf red.'vThese pointers are adapted to be displacedfatlan angle ,of 90"A withrespect to the main'dire'ction over adirection indicating scale U. I YDuring bearing by means of the framefan-J` tenna A; only,thesameis'placed Vinto therpofsi- It is obvious that the activation or."control :re`"

the recognition of the sense of direction isa-'f indicating pointer Z,likewise fastened on" the direction iinding wheel and adapted to bemoved It isV advisable to providel the surfaces 'throughv tion inawhichthe reception'is a minimum recept.,

tion. If hereby the Amain direction indicating pointer-Z points at thecalibration `0Vof thescale.

U itV Will be recognized that the directive ray forms with the directiondetermined by the iixed zero line. ofthe scale anV angle of a or anangle (M4-180). In order to 'determine the sense of direction thedirection indicating wheel is moved in either direction approximately90,V so that either'the blue auxiliary pointer B or theV redauxiliarypointer R is above the indicating line for Ythe angle a of the scale.The' blue auxiliary pointer may be assumed to be at this position. Now,the switch s (see Figure i) will be moved Y alternately several times totheyleft and the right the angle (c4-180).

resistances h1 and hzvand will -beleftto'remain upon the eld for whichthe signal strength is the greatest. VIf this is the field marked blueYthen the sense of direction corresponds with the position ofthe blueauxiliary pointer B' i. e. .with the. angle a". In the other case i. e'.if the greater signalV strength occurs at the positionV of the vpointerabovethe red iield, theV sense yof direction,4 offthe directive rayscorresponds with the position of the Vred rauxiliary pointer E, i. e.with Inthis manner .the "switch s can time be used as -an indicator forthe recognition of the sense ofV direction. y

Itis obvious that itis Within the' same spirit ofthe invention: if asdirective antenna instead of a closedvframe anV antenna ormed in anyother way, ,is used', such as an Adcock-antenna.

'An.embodimentA of this'type is shown in Fig-, ure 3 by Way of example.The directiveantenna is formed-'of two open vertical conductorsad,whichl are preferably arranged movable about a symmetrical axis betweenthese conductors.

- They two conductors da of the directive antenna are connected to .theintermediate circuit by means of coupling transformers Ick and whichcircuit suppliesthe input circuit of the Vhigh fre- Vquency ampliiierY ewhich forms the irst stage ofthe receiver.

The auxiliary antenna bis ar'- rangedat the center between theconductorsad. Otherwise rthe circuit for the auxiliary antenna corresponds withthat of Figure 1.

It :is advisable in particular when operating with very short waves toprovide the arnpliiiersVV didz with screen grids as shown in order to'prea. non-symmetrical signal absorption member, av

thermionici tubeconnected `therewith by way of ftunng means, and meansvfor determining the sense of direction of received signals comprisingarp'airY of thermionic tubes having'Y their anodes connected. todifferent sides of Ysaid absorption member, their control gridsconnected to a nondirection aerial, and means for alternately, renderingsaid last named tubes operative `and inoperative. Y Y

2i `Direction and sense of direction determining absorption systemcomprising, a directive aerial system, a Ynon-directive aerial, a pairof'thermionicy tubes having their-input electrodes connected to. saidnon-directional aerial, rand a connection between each terminaloi saiddirective aerial and they output electrode in one of'said tubes. y

3'. A direction finding system comprising inv combination a loop aerialconnected to a thermionic., tube having input and output circuits, anon-directional aerialV continuously coupled with at the same theinputcircuit of Vtwo thermionic tubes having the output" of each oneof saidtubes continuously connected tofopposite Asides of said loop aerial,means to determine the sense of direction, said lmeans controlling theactivation` ofreither one of said thermionic tubes which arecoupled withsaid non-directional aerial.

4. A direction nding system comprising in combination a loop aerialconnected to a thermionic tubehaving input and output circuits, anon-directional aerial continuously coupled with .the input circuit oftwo thermionic tubes having the output of each one of said Atubescontinuously connected to opposite sides of said loop aerial, means todetermine the sense of direction, switching means comprising 'a'fcommonswitch arm and separate variable resistance elements f to. Vvary theheater voltage of either one of: said thermionic tubes which are coupledwith said-non-directional aerial;V

5. A direction nding `system"co-mpri'singin combination a loop aerial'connected topa thei'-,r mionic tube havingxinput and output circuitsfanon-directionalaerial continuously coupled with the input circuit ofvvtwo screengrid tubes'having' the Youtput of each one of-jsaid tubescontinuously connected-to oppositeV sides: of said loop aerial, means todetermine .thesense of direction, said means controlling the activation'of either one ofsaid screen gridtubes which arecoupled with thenon-directional aerial.

f6'. A directive antenna system comprisingtwo openvertical conductors,said conductors arranged to'be movable about a symmetrical axis betweensaid conductors, transformer.- coupling.

Vertical conductor: couplings, means to detervmine thesense ofdirection, said means controlling theactivation ,ofeither oneof saidscreen grid tubes.V

7; A directive antenna'system'comprising two open verticalconductors,Vsaidconductors .ar-

ranged to be movable abouta symmetrical axisy between'said conductors,transformer coupling means for coupling said.conductors'toV the inputcircuit of a high frequency receiver: amplifier,y an auxiliary antennacontinuouslyvr connectedv with the inputV circuit of two screen gridtubes havingY theV output of each one of said tubes continuously`connectedY to oppositesides. ofsaid vertical conl vductor couplings,means'to determine the sense ofv direction, switching` means comprisinga com'- inon'switch arm and separate variable resistance elements tovary the heater Voltagelof: either one of said screen grid tubes'v whicharel coupled with the vertical conductorsf f' 8.` A direction iinding'system'comprisingv in combination a loop aerialconnected to athermionic tube having input and output'v circuitala non-directionalaerial continuously `coupledw'ith the input circuit of .two vthermionictubes'having the output lof each one of saidv tubes continuously.connected across condense'rs to opposite sides1of said loop aerial,meansto determinerthevsen'se offv directiongi said means controllingtheactivation of either lone of said thermionicltubes'which-arecoupled withsaid non-directionallaerial. 1 j

. WALTER Kmlnwmni '1 1

